Smoke cartridge



March 1969 E. D. CRANE ET AL SMOKE CARTRIDGE Filed April 14, 1967INVENTORS United States Patent 9" 7 Claims ABSTRACT OF THE DISCLOSURE Amanually ignited, narrow column colored smoke marker having a metallicfoil entirely encasing a smoke pellet and a portion of an igniting cordwith the other portion of said cord extending outside of said foil. Thesmoke composition consists of a mixture of methylaminoanthraquinone,indanthrene, thiourea, potassium chlorate and a binder.

The invention relates to a smoke marker and more particularly to amanually ignited marker for producing a narrow column of colored smokefor signaling purposes.

In the past smoke assemblies were constructed by either pressing loosepowder into a case, or by pressing or cementing a consolidated pelletinto a case. With these assemblies, additional measures had to be takento prevent the problem of flaming which has existed for many years inthe art of producing smokes. Production of a colored cloud depends on anexothermal chemical reaction vaporizing a dye which has been mixed withthe reactants. Subsequent condensation of the dye results in the coloredcloud formation. Destruction of the dye may occur by the oxygen in theair reacting combustively with the hot dye vapors causing what is knownin the art as flaming. Elimination of this flaming, other than throughcomposition modification, has been attempted by one or more of thefollowing methods used to build up pressure and to allow cooling of thedye vapor:

(a) Assembling into a container having one or more small openings.

(b) Keeping the surface of the composition at a distance from theopenings, and

(c) In the instances of assemblies with center holes in composition,inhibiting the ends so that burning does not occur at the ends of thecomposition.

These methods are not always completely successful in the elimination offlaming, moreover, in the encasing of composition, difliculties areencountered such as:

(a) Shrinking of paper cases when consolidating loose powder therein,and

(b) Inadequate inhibition of the sides of pellets when cementing intothe case.

The result of these methods was undesirable burning along the walls.

An advantage of the present invention is in its buoyancy. In instanceswhere it becomes necessary to place a smoke signal in a waterenvironment, the advantage of floating burning smoke cartridge will beapparent.

It is, therefore, an object of the present invention to provide a smokecartridge that does not present the problem of flaming.

Another object is the provision of a smoke cartridge having superiorcloud displays.

Still another object is to provide a smoke cartridge that is buoyant.

A further object is to provide a smoke cartridge having low size andweight for equivalent quantity of smoke composition.

The above objects as well as others together with the benefits andadvantages of the invention will be apice parent upon reference to thedetailed description set forth below, particularly when taken inconjunction with the drawings annexed hereto in which:

FIG. 1 shows a side view, partly broken away of the invention in theclosed inoperative condition.

FIG. 2 shows an isometric view of the invention in the open operativecondition.

FIG. 3 shows an exploded view of the invention.

As seen in the drawings the smoke cartridge 10 has an outer container12. which is covered by a screw cap 14 having a polyethylene liner (notshown), this being done for protection against moisture in theatmosphere. Enclosed inside the container 12 is the pellet-foil-ignitercord assembly 16. The assembly 16 consists of a consolidated smokepellet composition 18 wrapped in metal foil 20. On top of thecomposition 18 inside the foil 20 and extending therethrough is anigniter cord 22.

In the operation of the preferred assembly the igniter cord 22 is coiledon top of the composition 18 and the end of cord 22 emerges through thefolds of the foil 20, which has been folded snugly around and againstthe composition 18. The length of igniter cord extending outside thefoil wrapper is determined by safety considerations. For example, 2%inches (uncoiled) from initiating end to coil allows the operator from3-6 seconds to move away. The number of coils inside the foil wrapperdepends upon the composition used. The cord could also emerge through ahole cut into the foil.

As can be seen, no provisions for eliminating flame are required otherthan the foil wrap, which could be aluminum or the like, which allows aslight pressure buildup of insert gases formed by reaction, preventingoxygen in the atmosphere from diffusing in towards the reaction site.The dye vapors are cooled by contact with the metal foil before theyreach the atmosphere.

In addition to the elimination of flaming attained by using the methodof assembly of the invention disclosed herein, superior cloud displaysare accomplished compared to those attained with equivalent weight andvolume of smoke composition using prior methods. This superiorperformance is due to the burning that takes place on all surfaces ofthe smoke pellet, even though ignition starts at one surface, since thehot gases under the slight pressure developed, flow between the pelletand the foil to cause initiation on all surfaces. Even though the foilis wrapped around the pellet, the flexibility of the foil allows thegases to penetrate readily between the foil and pellet.

An example of composition yielding a red smoke is:

Percent Methylaminoanthraquinone 44.5 Indanthrene 5.0 Thiourea 19.8Potassium chlorate 29.7 Vinyl alcohol acetate resin 1.0

The smoke cartridge is 1.2" in diameter and 0.9" in height. Thecartridges are consolidated at 24,000 p.s.i. and wrapped in aluminumfoil with two coils of igniter cord inside the foil in contact with thesmoke composition. The total length of igniter cord used is 6%", theuncoiled portion being 2% inches long. Therefore about 43% of the cordis outside and 57% inside the foil wrapper. The igniter cord used is ofthe safety fuze type for example, type PL thermalite, or the like.

The system consists of a match head and striker comparable to theexisting smoke pot. Time of ignition is approximately six seconds. Theheat required to ignite the smoke composition is 400 C. when pellets ofcomposition are used and 200 C. when loose composition is used. Thealuminum container consists of thin gage aluminum with each sectionthreaded to form a water resistant container. The compressed smokepellet is wrapped in .001 in. thick aluminum foil.

The composition described above is used to provide a burning time ofabout fifteen seconds, but variations in percentage and particle size ofsome of the ingredients will yield different burning rates.

The composition can also be changed to provide for the use of differentdyes when different colors are necessary.

We claim:

1. In a manually ignited smoke marker for producing a narrow column ofcolored smoke for signalling purposes comprising:

a light weight container housing a compressed smoke composition and anigniter cord, said smoke composition consisting essentially ofmethylaminoanthraquinone, indanthrene, thiourea, potassium chlorate anda binder,

a metallic foil entirely encasing said composition and partiallyencasing said igniter cord, such that a portion of said cord is withinsaid foil and the remaining portion is outside said foil, whereby uponthe ignition of said cord, preliminary firing occurs outside of saidfoil wrapper and subsequent burning inside said foil Wrapper causes theburning of said smoke composition throughout the entire surface thereof.

2. A smoke cartridge of the type described in claim 1 wherein saidigniter cord extends through a cut in said metallic foil defining asmall opening.

3. A smoke cartridge of the type described in claim 1 wherein an end ofsaid igniter cord emerges through folds of said metallic foil whichdefine a small opening.

References Cited UNITED STATES PATENTS 1,448,073 3/1923 Lucas et a1102-90 1,918,594 7/1933 Fladger 1023l 3,102,477 9/1963' Stefan et a1.861 3,121,231 2/1964 Reaves et a1. 14984 3,338,763 8/1967 Kristal 14984OTHER REFERENCES AMC Pamphlet, AMCP 706187, Military PyrotechnicsSeries, part three, properties of materials used in pyrotechniccompositions, Oct. 31, 1963 (herein referred to as M.P.S.), p. 150required.

ROBERT F. STAHL, Primary Examiner.

U.S. Cl. X.R.

